(1) Field of the Invention
This invention relates to a sewer renovation system.
(2) Prior Art
Sewers can become damaged and sometimes blocked due to a number of causes, including earth movement, slime growth, tree root intrusion and pipe erosion due to hydrogen sulphide attacking the material of the sewer pipes.
The cost of digging up and replacing sewers is extremely high and various methods have been proposed for renovating existing but damaged sewer lines. According to one method presently used an inflatable tube is installed in the damaged sewer and, after it has been inflated, grout is pumped into the sewer pipe about the tube, which is removed after the grout has set. This method is very expensive and not fully reliable as the inflatable tube may be caused to collapse partially when the grout is pumped in, so that expensive and laborious correction work then becomes necessary.